Door latch mechanism

ABSTRACT

Herein disclosed is an improved door latch mechanism for typical use on the door of a motor vehicle. The latch mechanism has a toothed latch element and a detent means which has a pawl engageable with the toothed latch element. The latch element has unlatched, half-latched and fully latched positions and is moved for rotation by a striker which is fast on the vehicle body. The pivotal movement of the detent means relative to the latch element is controlled by combined actions of a lever arrangement which can be manually operable from the inside of the vehicle by the use of a garnish button or from the outside of the door with or without use of a key.

1 Apr. 16, 1974 1 DOOR LATCH MECHANISM [75] Inventors: Fumio Kobayashi; Koji Sasai, both of Yokohama, Japan [73] Assignee: Nissan Motor Company, Limited,

Yokohama City, Japan [22] Filed: Aug. 28, 1972 [21] Appl. No.: 284,267

[30] Foreign Application Priority Data Aug. 27, 1971 Japan 46-65079 [52] US. Cl. ..l 292/216, 292/DIG. 26 [51] Int. Cl. E05c 3/26 [58] Field of Search 292/216, 280, DIG. 26,

292/DIG. 27, DIG. 23, 198

[56] References Cited UNITED STATES PATENTS 3,190,682 6/1965 Fox 292/216 12/1970 Arlaushar 292/216 12/1972 Yoshimura 292/216 Primary Examiner-Robert L. Wolfe [5 7] ABSTRACT Herein disclosed is an improved door latch mechanism for typical use on the door of a motor vehicle. The latch mechanism has a toothed latch element and a detent means which has a pawl engageable with the toothed latch element. The latch element has unlatched, half-latched and fully latched positions and is moved for rotation by a striker which is fast on the vehicle body. The pivotal movement of the detent means relative to the latch element is controlled by combined actions of a lever arrangement which can be manually operable from the inside of the vehicle by the use of a garnish button or from the outside of the door with or without use of a key.

4 Claims, 6 Drawing Figures DOOR LATCH MECHANISM The present invention relates to a latch mechanism of the character commonly used on the doors of motor vehicles.

The latch mechanism herein disclosed is adapted to be locked from the inside of the motor vehicle by the use of a usual garnish button or from the outside of the door with or without use of a key. Once the latch mechanism is operated into the locked condition, the outside handle only idles even though it is worked upon from the outside of the door and, as a consequence, the parts and elements associated with the handle are subject to substantially no undue motions and actions which would otherwise result in impairment of the parts and elements. When the door happens to be closed with the latch mechanism preliminarily operated from the inside of the vehicle cabin to a position which is ready to be locked, the door will be unlocked and latched so that, in the event the driver has closed the door with the key left in the vehicle cabin, he can reopen the door through manipulation of the outside handle.

The latch mechanism according to the present invention basically comprises a body block, and a latch element pivoted on the block and having a ratchet portion provided with unlatched, half-latched and fully latched positions which are angularly spaced from each other. First biasing means urges the latch element to turn from the fully latched to unlatched position through the half-latched position. The block further carries thereon a detent means which is pivoted on the block and which has a pawl portion engageable with the ratchet portion of the latch element for holding the latch element in any one of the unlatched, half-latched and fully latched positions against the action of the first biasing means. The detent means has first and second abutments which are rotatable about an axis of rotation of the detent means. The detent means is urged by second bias ing means into engagement with the ratchet portion of the latch element. A locking lever is pivoted on the block and movable between locked and unlocked positions. A connecting member is rotatable on the locking lever and substantially linearly movable with rotation of the locking lever. The connecting member has an unlocking abutment and an unlatching abutment which are respectively engageable with the first and second abutments of the detent means. A detent actuating lever is pivoted on the block and movable between latching and unlatching position. This detent actuating lever is urged by third biasing means so as to turn from its unlatching to latching position and movably engages the detent means. The unlatching abutment of the connecting member is brought into engagement with the first abutment of the detent means for turning the detent means out of engagement with the ratchet portion of the latch element when the detent actuating lever is turned to the unlatching position with the locking lever in its unlocked position so that the latch element is allowed to turn into the unlatched position through the half-latched position by the action of the first biasing means. The unlatching abutment of the connecting member is moved out of alignment with the first abutment of the detent means when the locking lever is turned to the locked position. The unlocking abutment of the connecting member, on the other hand, is in the path for movement of the second abutment of the detent means when the detent actuating lever is in the latching position and concurrently the locking lever is in the locked position. The unlocking abutment of the connecting member is turned out of alignment with the second abutment of the detent means when the detent actuating lever is held in the unlatching position with the locking lever in the locked position.

In one preferred embodiment of the latch mechanism above described, the latch element and the detent means may be carried on one face of the body block and the locking lever, the detent actuating lever and t the connecting member may be carried on the other face of the block. In this instance, the first and second abutments of the detent means may be in the form of lateral extensions which appreciably project outwardly of the opposite face of the block through slots which are formed in the block. It is preferable that the locking lever be provided with biasing means which biases the locking lever to the locked or unlocked position. The detent actuating lever, on the other hand, may be formed with a slot which is elongated substantially in the direction parallel to the linear movement of the connecting member, in which instance the connecting member has a pin which is slidable in the elongated slot in the detent actuating lever.

It is the primary object of the present invention to provide an improved door closure means with a simple construction and yet having all the features required of modern latches, viz., idling of door handles when locked, keyless locking as required, and self-cancelling of locked condition when the door is erroneously locked and then shut.

Another object of the invention is to provide a simple and compact latch mechanism, through horizontal arrangements of operating parts on both sides of the body block.

Other features and advantages of the door latch mechanism according to the present invention will be come apparent from the following description of the present invention in which like reference numerals indicate corresponding parts and elements throughout the figures and in which:

FIG. 1 is a plan view of one side of the door latch mechanism according to the present invention;

FIG. 2 is a plan view of the other side of the door latch mechanism;

FIG. 3 is a side end view of the door latch mechanism illustrated in FIGS. 1 and 2;

FIG. 4 is a plan view similar to FIG. 2, but shows the latch mechanism in the half-latched position;

FIG. 5 is also similar to FIG. 2 but shows the latch mechanism in the fully latched position; and

FIG. 6 is a plan view still similar to FIG. 2 but illustrates the latch mechanism which is ready to be locked without use of a key.

Before entering into detailed descussion of the embodiment of the latch mechanism according to the present invention, it is to be noted that, although the latch mechanism is herein described as being used on the door structure of the motor vehicle, such is merely by way of example and, thus, the latch mechanism embodying the invention may find other useful applications for locking purposes. It should also be noted that the terms specifying the relative positions of the various parts and elements and the directions of the motions of such parts and elements are merely for the simplicity of illustration and, as such, are not limitative of the construction and operation of the latch mechanism according to the present invention.

Reference is now made to the accompanying drawings, first to FIGS. 1 to 3, wherein the latch mechanism is shown as being in an unlatched position. As noted previously, the latch mechanism embodying the present invention is adapted for use with a door (not shown) of a vehicle body so as to lock the door when the door is closed. The latch mechanism is thus cooperative with a striker (FIG. 2) which usually extends horizontally from a piller (not shown) of the vehicle body.

The latch mechanism includes a body block 12 which is usually formed of plastics. A latching element 14 is pivotally carried on one face of the block 12 through a pin 16. As best seen in FIG. 1, this latch element 14 has an inwardly curbed cam edge 18 defining a recess 20 to receive the striker 10. This recess 20 is located and configured in association with a passage 22 which is formed in the block 12. The passage 22 is opened edgewise of the block 12 and extends substantially horizontally of the vehicle body toward the striker 10 for the reason to be described later. The latch element 14 is urged to rotate about the pin 16 counter-clockwise in FIG. 1 or clockwise in FIG. 2 by means of a tension spring 24 which is secured at one end to the latch element and seated at the other to the block 12 opposite to the passage 22. The latch element 14 is further formed with a generally arcuate ratchet portion 26 which is located approximately opposite to the curved cam edge 18. The ratchet portion 26 comprises angularly spaced first, second and third external teeth 26a, 26b and 26c which are adapted to provide unlatched, half-latched and fully latched positions, respectively, of the latch mechanism as will be described later in more detail. For the purpose of limiting the counterclockwise rotation (in FIG. 1) of the latch element 14 as brought about by the action of the tension spring 24, the block 12 has therein a stop edge portion 28 with which the latch element 14 is engageable at its third or fully-latching tooth 26c when the latch element is rotated counter-clockwise as seen in FIG. 1.

The latch element 14 is cooperative with a detent means 30 which is also pivotally carried on the same face of block 12 through a pin 32. The detent means 30 is urged to turn clockwise in FIG. 1 by means of a tension spring 34 which is secured at one end to the detent means 30 and anchored at the other to the block 12. This detent means 30 has a pawl portion 36 which is engageable with any one of the external teeth 26a, 26b and 260 of the latch element 14 depending upon the relative angular positions of the latch element 14 and the detent means 30, respectively.

The position of the recess 20 in the latch element 14 relative to the passage 22 in the block 12 varies as the latch element 14 rotates about the pin 16. When the door is open and the latch element 14 engages at its first or unlatching tooth 26a with the pawl portion 36 of the detent means 30 as seen in FIG. 1, the recess 20 in the latch element 14 is aligned with and merges into the passage 22 in the block 12. When, on the other hand, the door is swung to the closed position; then the latch mechanism in its entirety is moved together with the door structure and admits the striker 10 into the passage 22 in the block 12. The striker 10 then abuts against the curved cam edge 18 of the latch element 14, which is consequently rotated about the pin 16 against the action of the tension spring 24 with the result that the second or half-latching tooth 26b and further the third or fully latching tooth 26c are brought into engagement with the pawl portion 36 of the detent means 30.

The detent means 30 has angularly spaced lateral extensions or tabs 38 and 40 projecting appreciably outwardly from the opposite face of the block 12 through slots 42 and 44, respectively, which are formed in the block 12 and which extend arcuately around the axis of rotation of the detent means 30 at predetermined central angles as seen in FIGS. 1 and 2. One lateral extension 38 is located adjacent the abutting edge of the pawl portion 36 while the other lateral extension 40 is located substantially at an uppermost portion of the detent means 30 or approximately at a right angle to the lateral extension 38. The lateral extensions 38 and 40 are thus movable through the arcuate slots 42 and 44, respectively, as the detent means 30 is rotated in either direction about the pin 32.

The block 12 carries on its opposite face a detent actuating lever 46 which is journaled to the block through a pin 48 located substantially intermediate between and generally in line with the pins 16 and 32 of the latch element 14 and the detent means 30, respectively, on the reverse side of the block 12. This detent actuating lever 46 is biased to rotate counter-clockwise in FIG. 2 by the action ofa coiled torsion spring 50 having one end connected to the pin 48 and the other end received on an arm portion 52 of the lever 46. The counter-clockwise rotation of the detent actuating lever 46 is limited by suitable stop means such as a stop pin 54 on the block 12 in a manner to be engageable with the arm portion 52 of the lever. The detent actuating lever 46 has another arm portion 56 extending generally in an opposite direction to the arm portion 52. The detent actuating lever 46 is further formed with an extension 60 extending approximately upwardly of the pin 48. This upward extension 60 has therein an elongated slot 62 which extends substantially vertically as seen in FIG. 2. The reason for the provision of this elongated slot 62 will be described later.

Below the detent actuating lever 46 in horizontal and parallel relationship is positioned a locking lever 64 which has opposed arm portions 66 and 68. The locking lever 64 is rockable about a pin 70 which is located intermediate the arm portions 66 and 68. The locking lever 64 is further formed with an extension 72 extending generally downwardly of the pin 70. An over-center spring 74 has one end anchored to this downward extension 72 and the other end anchored to the block 12. This over-center spring 74 acts in such a manner as to urge the locking lever 64 in one direction until it is subjected to an opposing force greater than a predetermined critical magnitude and to urge the locking lever in the reversed direction once such an opposing force is applied to the spring. When, thus, the locking lever 64 is moved in one direction, the over-center spring 74 first opposes such movement but snaps the locking lever when the locking lever turns through a dead point at which the direction of the biasing force of the spring reverses.

The locking lever 64 is connected at extreme ends of its arm portions 66 and 68 to control rods 76 and 78 which are adapted to move the locking lever 64 from inside and outside. respectively, of the vehicle body. Thus, one control rod 76 interconnects the arm portion 66 and a garnish button (not shown) positioned in the vehicle cabin while the other control rod 78 interconnects the arm portion 68 and a key member (not shown) which is operable from the outside of the door.

A connecting member 80 is rotatable on the locking lever 64 about a lateral tab 82 formed at its lower end portion and received in a slot 84 which is formed in the locking lever as seen in FIG. 2. The connecting member 80 extends substantially vertically of the block 12 and has a stepped top portion which is located in proximity to the arcuate slots 42 and 44 in the block 12 and to the upward extension 60 of the detent actuating lever 46. The connecting member 80 has in this stepped top portion a pin 86 which is slidably received in the elongated slot 62 formed in the upper extension 60. When, thus, the detent actuating lever 46 is rotated clockwise in FIG. 2 against the action of the torsion spring 50, then the connecting member 80 is accordingly rotated clockwise about the tab 82 through engagement between the upper pin 86 and the upward extension 60 of the lever 46. If, on the other hand, the locking lever 64 is rotated in either direction about the pin 70 from outside or inside of the vehicle body, then the connecting member 80 is moved upward or downward with the pin 86 guided in the elongated slot 62 in the upper extension 60 of the detent actuating lever 46.

The connecting member 80 further has an unlatching abutment 88 and an unlocking abutment 90, both formed on the stepped top portion of the connecting member. The unlatching abutment 88 is located in association with the lateral extension 40 of the detent means 30 when the connecting member 80 is in a raised position which is shown in FIG. 2. When, thus, the detent actuating lever 46 is turned clockwise in FIG. 2 about the pin 48, with the connecting member 80 in the raised position, then the unlatching abutment 88 of the connecting member 80 bears against the aligned edge of the lateral extension 40 of the detent means 30 so that the detent means 30 is caused to rotate clockwise in FIG. 2 about the pin 32 with the lateral extension 40 guided to the arcuate slot 44. The detent means 30 thus being turned counter-clockwise in FIG. 1, the pawl portion 36 of the detent means 30 is moved away from the ratchet portion 26 of the latch element 14 so as to allow the latch element to rotate in the unlatching direction from the fully latched position by the biasing force of the tension spring 24. If, on the other hand, the locking lever 64 is turned counter-clockwise in FIG. 2 about the pin 70 so as to lower the connecting member 80, then the unlatching abutment 88 is moved downwardly of the lateral extension 40 of the detent means 30. In this condition, the lateral extension 40 is free from the movement of the unlatching abutment 88 of the connecting member 80 and, as a consequence, the detent means 30 remains at rest even though the detent actuating lever 46 is rotated in the unlatching direction, viz., clockwise in FIG. 2.

The unlocking abutment 90, on the other hand, is in the form of a lateral extension which is engageable with the lateral extension 38 of the detent means 30. When the locking lever 64 is turned counter-clockwise in FIG. 2, the unlocking abutment 90 is located over the lateral extension 38 of the detent means 30 and, if the detent means 30 is rotated clockwise in FIG. 2 against the action of the tension spring 34, the abutment 90 is kicked out by the lateral extension 38 and accordingly raised so as to turn the locking lever 64 clockwise in FIG. 2 about the pin 70. As the locking lever 64 is thus rotated clockwise in FIG. 2, the over-center spring 74 snaps the locking lever 64 and now biases the locking lever 64 to the unlocked position shown in FIG. 2. When, on the other hand, the locking lever 64 is in the locked position and the detent actuating lever 46 is t turned to its unlatching position, then the connecting member is moved clockwise in FIG. 2 about the lateral flange 82, so that the unlocking abutment is out of the path of the lateral extension 38 of the detent means 30. Under this condition, the connecting member 80 and accordingly the locking lever 64 remain at rest even through the detent means 30 is turned about the pin 32.

Designated by reference numerals 92 and 94 in FIG. 3 are cover plates which are respectively attached to both faces of the block 12 for enclosing there-between the above described operating members and elements of the latch mechanism.

When, now, the door is open, the latch element 14 is in a position to have its recess 20 in alignment with the passage 22 in the block 12 in the absence of the striker 10 therein and its first or unlatching tooth 26a in engagement with the pawl portion 36 of the detent means 30 by the actions of the tension springs 24 and 34. The detent actuating lever 46 is concurrently turned and held in its counter-clockwise limit position with its arm portion 52 in abutting engagement with the stop pin 54 by the biasing force of the torsion spring 50, as illustrated in FIG. 2. The locking lever 64 is held in its clockwise limit position as seen in FIG. 2. The connecting member 80 is consequently held in the raised position to have its unlatching abutment 88 aligned with the lateral extension 40 of the detent means 30 and have its unlocking abutment 90 located vertically apart from the lateral extension 38 of the means 30.

When, now, the door of the motor vehicle isswung closed, the latch mechanism in its entirety is moved together with the door structure and admits the striker 10 in the passage 22 in the block 12. The striker 10 then abuts to the curved cam edge 18 of the latch element 14, which is consequently turned clockwise in FIG. 1 about the pin 16 against the action of the tension spring 24. The latch element 14 thus being rotated, the detent means 30 which is maintained in situ by the biasing force of the tension spring 34 has its pawl portion 36 pressed upon the ratchet portion 26 of the latch element 14 so that the second or half-latching tooth 26b and then the third or fully latching tooth 26c are brought into abutting engagement with the pawl por tion 36. When the door is moved to its fully closed position with the striker 10 positioned remotest from the passage 22 in the block 12, the latch element 14 assumes the fully latched position in. which the third or fully latching tooth 26c is in engagement with the pawl portion 36 of the detent means 30, as indicated by broken lines in FIG. 4. If, under this condition, an effort is applied to the door to open it, the latch element 14 is prevented from'turning clockwise in FIG. 4 by engagement between the tooth 26c and the pawl portion 36 of the detent means 30 with the result that the striker 10 remains captured in the recess 20 in the latch element 14. The door can not be opened in this manner.

If, in this instance, the detent actuating lever 46 is turned about the pin 48 in the unlatching direction, viz., clockwise in FIG. 4 against the opposing force of the torsion spring 50, the connecting member 80 is turned about the lateral tab 82 clockwise in FIG. 4 through engagement between the pin 86 and the upper extension 60 receiving the pin 86 in its elongated slot 62. The unlatching abutment 88 of the connecting member 80 therefore engages and presses upon lateral extension 40 of the detent means 30. The lateral extension 40 of the detent means 30 is then moved through the arcuate slot 44 in the block 12 so that the detent means 30 is caused to turn clockwise in FIG. 4 about the pin 32 against the action of the tension spring 34. This causes the pawl portion 36 of the detent means 30 to be disengaged from the third or fully latching tooth 26c of the latch element 14, allowing the latch element 14 to freely rotate.

If, however, the locking lever 64 is turned counterclockwise in FIG. 4 about the pin 70 from inside or outside of the vehicle body through the control rod 76 or 78, respectively, then the connecting member 80 is lowered to have its unlatching abutment 88 moved out of alignment with the lateral extension 40 of the detent means 30, as seen in FIG. 5. In this condition, the unlatching abutment 88 of the connecting member 80 passes clear of the lateral extension 40 even though the member 80 is turned clockwise in FIG. by clockwise rotation of the detent actuating lever 46. The pawl portion 36 of the detent means 30 is thus kept in engagement with the third or fully latching tooth 260 of the latch element 14.

If the detent actuating lever 46 is worked upon in this locked condition of the latch mechanism, the connecting member 80 held in the lowered position is unable to exercise an action on the detent means 30 as previously discussed, and the detent actuating lever 46 merely idles and thus imparts no mechanical pressure to the associated operating elements, which are therefore saved from undergoing undue stresses.

As previously noted, the latch mechanism of the construction above described is adapted for the keyless locking of the door of the motor vehicle.

For this purpose, the locking lever 64 should first be turned to the locked position, viz., counter clockwise from the position shown in FIG. 2, and furthermore the detent actuating lever 46 should be turned to and held in the unlatching position, viz., clockwise in FIG. 2, before the door is closed. In this condition, the unlocking abutment 90 of the connecting member 80 is out of the path of the lateral extension 38 as seen in FIG. 6. The door should then be closed and thereafter the detent actuating lever 46 should be released so as to be allowed to turn counter-clockwise in FIG. 6 by the action of the torsion spring 50, thereby establishing the locked condition which is illustrated in FIG. 5.

The latch mechanism according to the present invention is. furthermore, adapted to be prevented from being locked in the event the door is closed with the locking lever 64 preliminarily moved to the locked position. When, thus, the door is closed with the latch mechanism in the locked condition shown in FIG. 5, the latch element is turned by the striker advancing into the latch mechanism and thus moves appreciably upwardly the pawl portion 36 of the detent means 30 against the action of the tension spring 34 as the second and third teeth of the latch element engage the pawl portion 36 of the detent means 30. When the detent means 30 is turned clockwise in FIG. 5, the lateral extension 38 of the detent means 30 presses upon the unlocking abutment 90 of the connecting member 80 from the underside of the unlocking abutment. The connecting member is accordingly raised so as to cause the locking lever 64 to turn clockwise in FIG. 5 against the biasing force of the over-center spring 74 (FIG. 2). When the load on the spring 74 exceeds the predetermined magnitude, then the locking lever 64 snaps to the position shown in FIG. 4 with the result that the latch mechanism in its entirety is rendered into the unlocked condition. The door now can be opened if the detent actuating lever 46 is so manipulated as to turn clockwise in FIG. 4. If, thus, the driver of the motor vehicle has set the locking lever 64 to the locked position from inside the vehicle cabin and has closed the door with a locking key inadvertently left in the cabin, he can open the door simply by turning the detent actuating lever 46 from the outside.

What is claimed is:

l. A door latch mechanism comprising, in combination, a body block, a latch element pivoted on said block and including a ratchet portion having unlatched, half-latched and fully latched positions which are angularly spaced from each other, first biasing means for urging said latch element to turn from the fully latched position to the unlatched position through v,the halflatched position, a detent means pivoted on said block and having a pawl portion engageable with said ratchet portion of the latch element for holding the latch element in any one of said positions, said detent means having first and second abutments which are rotatable about an axis of rotation of the detent means, second biasing means for urging said detent means into engagement with said ratchet portion of the latch element, a locking lever pivoted on said block and movable between locked and unlocked positions, a connecting member rotatable on said locking lever and substantially linearly movable with concurrent rotation of said locking lever, said connecting member having an unlocking abutment and an unlatching abutment which are respectively engageable with said first and second abutments of said detent means, a detent actuating lever pivoted on said block and movable between latching and unlatching positions, third biasing means for urging said detent actuating lever to turn from said unlatching position to said latching position, said connecting member movably engaging said detent actuating lever, said unlatching abutment of said connecting member engaging said first abutment of said detent means for turning the detent means out of engagement with said ratchet portion of said latch element when said detent actuating lever is turned to the unlatching position with said locking lever in said unlocked position, thereby allowing the latch element to turn by the action of said first biasing means, said unlatching abutment of the connecting member being moved out of alignment with said first abutment of the detent means when said locking lever is turned to the locked position, said unlocking abutment of said connecting member being in alignment with said second abutment of said detent means when said detent actuating lever is in said latching position and concurrently said locking lever is in said locked position, said unlocking abutment being out of alignment with said second abutment when said detent actuating lever is in said unlatching position with said locking lever in said locked position, and cam means on said latch element for turning the latch element from said unlatched position to said fully latched position when said latch mechansim is operated for a latched condition, and in which said latch element and said detentmeans are carried on one face of said block and said locking lever, said detent actuating lever and said connecting member are carried on the other face of the block and in which said first and second abutments of said detent means are in the form of lateral extensions which project appreciably from said other face of the block through slots formed in the block.

2. A door latch mechanism comprising, in combination, a body block, a latch element pivoted on said block and including a ratchet portion having unlatched, half-latched and fully latched positions which are angularly spaced from each other, first biasing means for urging said latch element to turn from the fully latched position to the unlatched position through the halflatched position, a detent means pivoted on said block and having a pawl portion engageable with said ratchet portion of the latch element for holding the latch element in any one of said positions, said detent means having first and second abutments which are rotatable about an axis of rotation of the detent means, second biasing means for urging said detent means into engagement with said ratchet portion of the latch element, a locking lever pivoted on said block and movable between locked and unlocked positions, a connecting member rotatable on said locking lever and substantially linearly movable with concurrent rotation of said locking lever, said connecting member having an unlocking abutment and an unlatching abutment which are respectively engageable with said first and second abutments of said detent means, a detent actuating lever pivoted on said block and movable between latching and unlatching positions, third biasing means for urging said detent actuating lever to turn from said unlatching position to said latching position,said connecting member movably engaging said detent actuating lever, said unlatching abutment of said connecting member engaging said first abutment of said detent means for turning the detent means out of engagement with said ratchet portion of said latch element when said detent actuating lever is turned to the unlatching position with said locking lever in said unlocked position, thereby allowing the latch element to turn by the action of said first biasing means, said unlatching abutment of the connecting member being moved out of alignment with said first abutment of the detent means when said locking lever is turned to the locked position, said unlocking abutment of said connecting member being in alignment with said second abutment of said detent means when said detent actuating lever is in said latching position and concurrently said locking lever is in said locked position, said unlocking abutment being out of alignment with said second abutment when said detent actuating lever is in said unlatching position with said locking lever in said locked position, and cam means on said latch element for turning the latch element from said unlatched position to said fully latched position when said latch mechanism is operated for a latched condition, and in which said detent actuating lever has therein a slot which is elongated substantially in the direction of the linear movement of said connecting member and in which said connecting member has a pin which is slidable in said slot in the detent actuating lever.

3. A door latch mechanism as claimed in claim 1, further including cover plates which are respectively attached to the both faces of said body block, thereby enclosing therebetween the operating members which are located in the block.

4. A door latch mechanism as claimed in claim 3, in which each of said latch element and said detent means is carried on one of said cover plates through a headless pin and each of said locking lever and said detent actuating lever is carried on the other of said cover plates through a headless pin.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 04,441

DATED 1 Apr. 16, 1974 INVENTOMS) I Fumio Kobayashi, et a1 ltis certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shownbelow:

On the title page item[73] should read -Nissan Motor Company, Limited and Ohi Seisakusho Company, I Limited, both of Yokohama City, Japan-- Signed and Scaled this sixteenth Day of March 1976 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting olf Commissioner ofPate'nls and Trademarks 

1. A door latch mechanism comprising, in combination, a body block, a latch element pivoted on said block and including a ratchet portion having unlatched, half-latched and fully latched positions which are angularly spaced from each other, first biasing means for urging said latch element to turn from the fully latched position to the unlatched position through the half-latched position, a detent means pivoted on said block and having a pawl portion engageable with said ratchet portion of the latch element for holding the latch element in any one of said positions, said detent means having first and second abutments which are rotatable about an axis of rotation of the detent means, second biasing means for urging said detent means into engagement with said ratchet portion of the latch element, a locking lever pivoted on said block and movable between locked and unlocked positions, a connecting member rotatable on said locking lever and substantially linearly movable with concurrent rotation of said locking lever, said connecting member having an unlocking abutment and an unlatching abutment which are respectively engageable with said first and second abutments of said detent means, a detent actuating lever pivoted on said block and movable between latching and unlatching positions, third biasing means for urging said detent actuating lever to turn froM said unlatching position to said latching position, said connecting member movably engaging said detent actuating lever, said unlatching abutment of said connecting member engaging said first abutment of said detent means for turning the detent means out of engagement with said ratchet portion of said latch element when said detent actuating lever is turned to the unlatching position with said locking lever in said unlocked position, thereby allowing the latch element to turn by the action of said first biasing means, said unlatching abutment of the connecting member being moved out of alignment with said first abutment of the detent means when said locking lever is turned to the locked position, said unlocking abutment of said connecting member being in alignment with said second abutment of said detent means when said detent actuating lever is in said latching position and concurrently said locking lever is in said locked position, said unlocking abutment being out of alignment with said second abutment when said detent actuating lever is in said unlatching position with said locking lever in said locked position, and cam means on said latch element for turning the latch element from said unlatched position to said fully latched position when said latch mechansim is operated for a latched condition, and in which said latch element and said detent means are carried on one face of said block and said locking lever, said detent actuating lever and said connecting member are carried on the other face of the block and in which said first and second abutments of said detent means are in the form of lateral extensions which project appreciably from said other face of the block through slots formed in the block.
 2. A door latch mechanism comprising, in combination, a body block, a latch element pivoted on said block and including a ratchet portion having unlatched, half-latched and fully latched positions which are angularly spaced from each other, first biasing means for urging said latch element to turn from the fully latched position to the unlatched position through the half-latched position, a detent means pivoted on said block and having a pawl portion engageable with said ratchet portion of the latch element for holding the latch element in any one of said positions, said detent means having first and second abutments which are rotatable about an axis of rotation of the detent means, second biasing means for urging said detent means into engagement with said ratchet portion of the latch element, a locking lever pivoted on said block and movable between locked and unlocked positions, a connecting member rotatable on said locking lever and substantially linearly movable with concurrent rotation of said locking lever, said connecting member having an unlocking abutment and an unlatching abutment which are respectively engageable with said first and second abutments of said detent means, a detent actuating lever pivoted on said block and movable between latching and unlatching positions, third biasing means for urging said detent actuating lever to turn from said unlatching position to said latching position, said connecting member movably engaging said detent actuating lever, said unlatching abutment of said connecting member engaging said first abutment of said detent means for turning the detent means out of engagement with said ratchet portion of said latch element when said detent actuating lever is turned to the unlatching position with said locking lever in said unlocked position, thereby allowing the latch element to turn by the action of said first biasing means, said unlatching abutment of the connecting member being moved out of alignment with said first abutment of the detent means when said locking lever is turned to the locked position, said unlocking abutment of said connecting member being in alignment with said second abutment of said detent means when said detent actuating lever is in said latching position and concurrently said locking lever is in said locked pOsition, said unlocking abutment being out of alignment with said second abutment when said detent actuating lever is in said unlatching position with said locking lever in said locked position, and cam means on said latch element for turning the latch element from said unlatched position to said fully latched position when said latch mechanism is operated for a latched condition, and in which said detent actuating lever has therein a slot which is elongated substantially in the direction of the linear movement of said connecting member and in which said connecting member has a pin which is slidable in said slot in the detent actuating lever.
 3. A door latch mechanism as claimed in claim 1, further including cover plates which are respectively attached to the both faces of said body block, thereby enclosing therebetween the operating members which are located in the block.
 4. A door latch mechanism as claimed in claim 3, in which each of said latch element and said detent means is carried on one of said cover plates through a headless pin and each of said locking lever and said detent actuating lever is carried on the other of said cover plates through a headless pin. 